Patent Document 1 discloses a golf club head, in which a metal granular body is sealed in the golf club head such that the metal granular body is concentrated on a central part (position opposing a sweet spot of a face plate) of a rear part of the head at the time of swinging of a golf club and the metal granular body is collided with the sweet spot of the face plate at the moment the club head impacts a golf ball, so that a rebounding force of the face plate is enhanced to thereby increase the driving distance.
[Patent Document 1] Official Gazette of Japanese Patent Application Laid-Open No. H08-155059